The invention relates to a surgical instrument for impact insertion of a trocar-needle into a bone for the purpose of connecting to the needle an infusion or transfusion set or a syringe containing any medicine to be injected for medical treatment of a human or animal patient. It relates particularly to an instrument suitable for instantaneous insertion of a trocar-needle, be it in a battle field, the site of an accident, or any other occasion where instantaneous infusion or itravascular injection becomes necessary. It is especially necessary in the case of newborns or children where it is often difficult to find a vein. But also with adults it often becomes necessary to find an alternative route to intravenous infusion, for rapid vascular access. Likewise for the purpose of marrow aspiration or transplantation.
Intraosseous infusion and bone marrow transfusion was first introduced in the forties of this century, and was especially used in emergency cases during World War II, to avoid the lengthy times needed for finding the suitable blood vessel for insertion of the needle. Nowadays the method is well known, but not much in use, because of the difficulty to forcefully drive a needle or a trocar into the bone with resulting great pain, on the one hand, and the danger of infection owing to the necessity to provide an opening through the skin and the tissue surrounding the bone. The conventional trocar used is in the form of a sharp stylet enclosed in a tube (cannula) and inserted through the containing wall of the bone, whereafter the stylet is withdrawn permitting fluid to be infused or to be drained through the tube.
Infusion, injection of drugs, resuscitation and anesthesis through a major vein or peripheral vein often cause complications which can easily be avoided by intraosseous infusion. There exist a few medical instruments for intraosseous infusion injection or aspiration, but they differ considerably from the present device which is characterized by the operation of forcefully driving a trocar needle into the bone, releasing it from the device and leaving it in the bone for subsequent attachment of the needle to a syringe, an infusion or transfusion set.
The following patents are cited as prior art, but they differ from the present device in their essential functions:
U.S. Pat. No. 4,969,870 (Kramer et al.) describes a tube having an upper end for connection of an infusion set and an enlarged lower end which is rotatably advanced through the cortical bone into the trabecular bone.
U.S. Pat. No. 5,271,744 (Kramer et al.) discloses a device for rapid vascular drug delivery, including a syringe body fitted with a needle. A compressed helical spring is released to drive a plunger into the syringe body and simultaneously driving the needle into the bone and injecting the drug. A second helical spring serves to extract the needle immediately after the medication has been injected.
It is the main object of the present invention to provide a specially designed trocar-needle and an instrument which will drive it into the bone while causing almost no pain to the patient due to high velocity penetration of the trocar-needle, and to leave it in situ for infusion, transfusion aspiration, and other medical treatment.
It is another object of the present invention to provide an instrument which will automatically insert the needle into the bone to a predesignated depth.
Still another object is to provide an instrument for the above purpose which is practically foolproof and easily handled by any surgeon, nurse, medic or paramedic in the battlefield, as well as in ambulances, air transport and especially in the emergency room of a hospital or a ward, and in any occasion as an alternative to intravenous injection, infusion or other medical treatment.
Still another object is to provide a surgical instrument which can be readily sterilized for re-use, but the main idea is to produce it at low cost so as to permit its disposal after a single use.